B7-H1 up-regulation on dendritic-like leukemia cells suppresses T cell immune function through modulation of IL-10/IL-12 production and generation of Treg cells
✍ Scribed by Wei Ge; Xiaotong Ma; Xin Li; Yafei Wang; Changhong Li; Hengxing Meng; Xiaofan Liu; Zhen Yu; Shengguo You; Lugui Qiu
- Book ID
- 104040954
- Publisher
- Elsevier Science
- Year
- 2009
- Tongue
- English
- Weight
- 596 KB
- Volume
- 33
- Category
- Article
- ISSN
- 0145-2126
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✦ Synopsis
Dendritic-like leukemia cells (DLLC) originating from leukemic cells could potentially induce a T cell-mediated anti-leukemia immune response. It has been demonstrated that B7-H1, a newly identified homologue of CD80/CD86, is abundant in human carcinomas and dendritic cells (DC), can exert co-stimulatory and immune regulatory functions. We demonstrated that B7-H1 was significantly expressed on AML cells and was strongly enhanced after differentiation to DLLC. Blockade of B7-H1 expressed on DLLC results in increased T cell proliferation and Th1 cytokine production, and decreased Th2 cytokine production. Importantly, autologous CTLs induced by DLLC treated with B7-H1 mAb showed significantly increased specific cytotoxcity against AML blasts. We further demonstrated that a significant decrease in IL-12 production, increase in IL-10 production by DLLC, and an increased CD4(+)CD25(+)Foxp3(+) T regulatory population lead to the defective T cell immune response that is induced by B7-H1 up-regulation on DLLC. Our data suggest that up-regulated B7-H1 on DLLC acts as a strong inhibitor of anti-leukemia T cell response, and that blockade of B7-H1 can improve DLLC-mediated anti-leukemia immunity.